The invention relates to pipe joints or couplings, but more particularly, the invention relates to a female coupling with a locking means of the staple type.
Quick-connecting couplings have widespread use in the hydraulic industry. This invention applies to quick-connecting couplings of the type that receives a male-stem fitting that is usually attached to each end of a hydraulic hose. The male stem has a collar for retaining it in a stem-receiving bore of the female coupling. A removable staple intersects the bore behind the male stem collar which locks the assembled pieces together.
One class of female coupling has a U-shaped staple that must be completely removed before the male stem can be inserted. A problem with this class of couplings is that the staples are easily lost and require constant replacement. Some staples have legs with outwardly projecting barbs that are biased against a female coupling for the purpose of retaining the staple to prevent unwanted dislodgement during use. The problem with this particular type of staple is that it is very difficult to remove as the ends of the staple must be forced together before it can be pried from a coupling.
Another class of a coupling uses a staple that has centrosymmetrical sector-shaped slots on its legs which face each other and constantly intersect a stem-receiving bore. A male stem with a chamfered collar is inserted in the bore and pressed against the slots spreading the legs of the staple and permitting passage of the collar. The legs snap together behind the collar to retain the stem. A problem with this type of coupling is that it is suitable only for low pressure applications. Also, a longitudinal force must be applied to the male end to effect coupling. In some applications, such pressure on the end of the hose may be difficult, if not impossible, to apply.